1. Field of the Invention
This invention relates, in general, to dentures and, more specifically, to inserts for retaining a denture in the mucosal tissue of a patient.
2. Description of the Prior Art
Millions of people today require full or partial dentures to replace missing teeth. With a partial denture, the denture can be securely anchored to the surrounding teeth for full retention.
However, when a full denture is required, anchoring the denture to surrounding teeth is not possible and other securing or anchoring means must be employed. A common retention means is the use of an adhesive to hold the denture in place on the mucosal tissue of the mouth. However, such adhesives have not been fully effective in creating a stable and secure mounting of the denture and commonly result in movement and/or slippage of the denture.
Another means for securely retaining a denture in position which is finding widespread use today is the use of an intermucosal insert. As shown in U.S. Pat. No. 3,905,108, the insert is a small metallic projection having a base, an elongated neck and a mushroom-shaped head. The base of the insert is mounted in a cavity on the denture and is held in place by an adhesive, such as acrylic cement. The neck and head of the insert project outward from the denture and are adapted to be inserted into a suitably formed cavity in the mucosal tissue surrounding the jawbone of a patient. After insertion of the insert into the cavity, the surrounding mucosal tissue heals and grows around the neck and head of the insert within a short period of time to form a secure and resilient socket for the insert.
However, the use of such previously devised intramucosal inserts has not been without problems. Such inserts are mounted in the denture by means of an acrylic cement which requires several hours to harden thereby prolonging the construction time of the denture. Furthermore, despite precautions such as the use of a plastic sleeve surrounding the neck of the insert, etc., excess acrylic cement invariably is deposited on the upper surface of the base of the insert and on the denture thereby requiring time-consuming cleaning and grinding operations to remove the excess cement so as to provide a smooth surface on the denture which would not irritate the adjoining mucosal tissue.
Another problem encountered with the use of such inserts involves the formation of a cavity in the mucosal tissue for receiving the neck and head of the insert. The position of the cavity is difficult to accurately establish since a plurality, typically fourteen, inserts are employed in a full upper or lower denture. The inserts are arranged in two offset rows on either side of the palatial slope and the ridge crest of the denture. The inserts are secured in position on the denture prior to the preparation of the receptor cavities in the mucosal tissue. This often results in mis-positioning of the receptor cavity and causes misalignment of the inserts when the inserts are inserted into the mouth of the patient. During such installation, the palatial inserts slide along the ridge and do not fully seat within the palatial receptor cavities thereby resulting in a misfit of the denture and less than full retention.
Finally, the receptor cavitites in the mucosal tissue are formed by using a burr which forms an elongated, cylindrical cavity within the mucosal tissue. The cavity has a diameter only slightly smaller than the width of the head of the insert such that the head of the insert is slidably inserted into the cavity in a snug fashion prior to regrowth of the surrounding tissue around the neck and head of the insert. However, due to the resilient nature of the mucosal tissue, the tissue tends to force the insert out of the cavity before the tissue can fully regrow around the insert thereby resulting in a partial disengagement of the insert from the cavity and a resultant poor fit of the denture on the tissue.
Further, as the cavity is formed with a diameter approximately equal to the diameter of the head of the insert, a large space is created between the sides of the cavity and the much narrower diameter of the neck of the insert. This has prevented the tissue from forming a solid cuff completely around the neck of the insert and, in some cases, has resulted in complete non-adhesion of the tissue to the neck of the insert.
Thus, it would be desirable to provide an intramucosal insert which overcomes the problems of previously devised intramucosal inserts in providing a secure retention of a denture on the mucosal tissue of a patient. It would also be desirable to provide an intramucosal insert which is able to be more securely retained within the mucosal tissue. It would also be desirable to provide an intramucosal insert which may be mounted on the denture in a simple and quick manner. Finally, it would be desirable to provide an intramucosal insert and method for retaining a denture on the mucosal tissue of a patient which provides a more secure retention of the denture on the tissue.